Heleopera petricola is not uncommon in wet bog sphagnum. Unfortunately water samples from this source usually are quite untidy, with sphagnum leaves and other debris spoiling the view. So it is a challenge to view a tidy specimen. Here is a nice 135 µm high specimen:

Heleopera (greek helos = bog, pera = bag) are flat, purse-shaped with a slit mouth. This specimen is in the resting or dormant stage called cyst, which helps the organism to survive in unfavorable environmental conditions, like winter.

Hallo Hans,
thank you for showing these great images!
At the MIKRO Hamburg we haven't covered amoebes at least since 1989.
I'm still looking for a way to trick you into doing a presentation of the topic....